A karaoke apparatus is a machine for accompanying songs developed in Japan, with which the user sings into a microphone while playing back the accompanying music pre-recorded in the recording medium. The karaoke apparatus has recently been equipped with various functions such as a key control function (tonal pitch variable function) and an echo effect function so that the singer can sing songs more easily.
An example of the prior art of the conventional karaoke apparatus provided with a key control function is disclosed in the Japanese Patent Provisional Publication No. 204095/84, "Tonal pitch variable apparatus" which is incorporated herein by reference. In the conventional apparatus disclosed therein, the singer manipulates the apparatus to check the pitch of a tune recorded in the accompaniment recording medium for karaoke before singing the song, while the apparatus instructs the singer to produce voice to check the register of the singer, and the two are compared. The pitch of the tone is controlled depending on the result.
The constitution of the disclosed conventional tonal pitch variable apparatus comprises frequency analysis means for analyzing the frequency of the input signal to determine the pitch, register check means for preliminarily checking the registers of two different kinds of sound signals, that is, the accompaniment music signal and sound signal produced by the singer, separately entered from the result of pitch judgment by the frequency analysis means, frequency shift degree determining means for determining the frequency shift degree from the registers of two input sound signals checked by the register check means, and frequency shift means for shifting the frequency of one input sound by the shift degree determined by the frequency shift degree determining means.
In a thus composed conventional tonal pitch variable apparatus, the operation is described below.
First of all, a necessary portion of the accompaniment recording medium for karaoke, for example, the first chorus of the tune the singer is going to sing, is reproduced, and is fed into the frequency analysis means, the highest sound and lowest sound of the accompaniment recording medium for karaoke reproduced by using the register check means are checked.
Then the singer's voice is entered in the frequency analysis means. The singer sings do, re, mi, and so forth sequentially within the singer's own register. The voice of the singer is analyzed by the frequency analysis means, and the register of the singer is obtained by the register checkmeans.
In this way, the register of the tune recorded in the accompaniment recording medium for karaoke and the register of the singer are obtained. These registers are compared in the frequency shift degree determining means, and the frequency (pitch) shift degree is determined. For example, when the register of the accompaniment recording medium for karaoke is higher than the register of the singer, the frequency shift degree is determined so as to lower the pitch of the accompaniment recording medium for karaoke. Depending on this frequency degree, the reproduction pitch of the accompaniment recording medium for karaoke is lowered by the frequency shift means, so that reproduced sound in a pitch suited to the register of the singer is obtained.
In such a conventional constitution, the manipulation is complicated. That is, the necessary portion of the accompaniment recording medium for karaoke must be reproduced, and the register of the singer must be checked. It takes a long time until the singer can actually start singing to the karaoke. When many people enjoy the use of the karaoke, such manipulation is practically impossible.